We propose to evaluate the hepatic metabolism of exogenous glucagon in an in vivo dog model, to study the effect of certain factors on this process (in particular changes in nutrient and fasting conditions and exogenous insulin administration) and to define the contributions of hepatic, renal and splanchnic glucagon extractions to the overall metabolic clearance rate of this hormone (MCR Glucagon). In addition we will attempt to relate hepatic glucagon metabolism to hepatic glucagon receptor status. The metabolism of somatostatin will be investigated simultaneously.